Metal concentrations in fish, crabs, and bivalve molluscs from marine waters adjacent to a multi-metals smelter and refinery.

Metal concentrations were determined in tissues of finfish, crabs, and bivalve molluscs collected from marine waters near Port Pirie, South Australia, the site of a long-standing multi-metals smelter and refinery. A general trend of tissue metal concentrations in order of highest to lowest was observed in bivalves > crabs > finfish. A lead concentration of 158 ± 6.

In vitro nuclear receptor inhibition and cytotoxicity of hydraulic fracturing chemicals and their binary mixtures.

The widespread use of hydraulic fracturing (HF) in oil and gas extraction operations has led to concern over environmental risks posed by chemicals used in HF fluids. Here we employed a suite of stable luciferase reporter gene assays to investigate the potential for selected HF chemicals or geogenics to activate or antagonise nuclear receptor signalling. We screened three biocides (bronopol [BP], glutaraldehyde [GA], and tetrakis(hydroxymethyl)phosphonium sulfate [THPS]), a surfactant (2-butoxyethanol), a friction reducer (polyacrylamide), and a coal seam geogenic (o-cresol) for their potential to act as agonists or antagonists of the estrogen receptor, androgen receptor, progesterone receptor (PR), glucocorticoid receptor or peroxisome proliferator-activated receptor gamma (PPARγ).

Environmental pollution affects molecular and biochemical responses during gonadal maturation of Astyanax fasciatus (Teleostei: Characiformes: Characidae).

Endocrine disrupting compounds (EDCs) have the potential to alter fish reproduction at various levels of organization. The aim of this study was to assess the impact of a natural environment with heavily anthropogenic influence on the physiological processes involved in reproduction in the freshwater fish lambari (Astyanax fasciatus) using different biomarkers. Adult males and females were collected in different seasons from two distinct sites in the same watershed: Ponte Nova Reservoir (PN) considered a pristine or small anthropogenic influence reference point; and Billings Reservoir (Bil), subjected to a large anthropogenic impact.

De novo assembly and analysis of changes in the protein-coding transcriptome of the freshwater shrimp Paratya australiensis (Decapoda: Atyidae) in response to acid sulfate drainage water.

Background: The atyid shrimp Paratya australiensis occurs in surface freshwater habitats throughout eastern Australia and has been used to study the ecotoxicology of contaminants such as pesticides and metals. The acidification of surface water that can occur after acid sulfate material in soils and sediments is oxidised and subsequently re-wetted is a serious environmental issue in coastal regions and inland riverine floodplains worldwide. Solubilisation of soil-associated minerals can result in high waterborne concentrations of mineral salts and dissolved metals, which together with low pH represent a potential threat to aquatic ecosystems in affected regions.

In vitro nuclear receptor activity and in vivo gene expression analysis in Murray-Darling rainbowfish (Melanotaenia fluviatilis) after short-term exposure to fluoxetine.

Fluoxetine (FLX) is one of numerous pharmaceuticals found in treated municipal wastewater discharged to the environment. In the present study, we investigated the effects of short-term (96h) waterborne FLX exposure (1μg/L or 100μg/L) on the expression of selected genes in brain, liver, and gonads of female Murray-Darling rainbowfish (Melanotaenia fluviatilis), a small-bodied teleost of ecotoxicological relevance in the Australasia region. Plasma 17β-estradiol (E2) levels were also determined.

Identification of Putative Nuclear Receptors and Steroidogenic Enzymes in Murray-Darling Rainbowfish (Melanotaenia fluviatilis) Using RNA-Seq and De Novo Transcriptome Assembly.

Murray-Darling rainbowfish (Melanotaenia fluviatilis [Castelnau, 1878]; Atheriniformes: Melanotaeniidae) is a small-bodied teleost currently under development in Australasia as a test species for aquatic toxicological studies. To date, efforts towards the development of molecular biomarkers of contaminant exposure have been hindered by the lack of available sequence data. To address this, we sequenced messenger RNA from brain, liver and gonads of mature male and female fish and generated a high-quality draft transcriptome using a de novo assembly approach.

Tracking multiple modes of endocrine activity in Australia's largest inland sewage treatment plant and effluent- receiving environment using a panel of in vitro bioassays.

Estrogenicity of sewage effluents, and related ecotoxicological effects in effluent-receiving environments, have been widely reported over the last 2 decades. However, relatively little attention has been given to other endocrine pathways that may be similarly disrupted by a growing list of contaminants of concern. Furthermore, the Australian evidence base is limited compared with those of Europe and North America.

Nortestosterone-derived synthetic progestogens do not activate the progestogen receptor of Murray-Darling rainbowfish (Melanotaenia fluviatilis) but are potent agonists of androgen receptors alpha and beta.

Synthetic progestogens derived from 19-nortestosterone can elicit a number of adverse effects in fish including decreased fecundity, altered hormone levels, disruption of normal breeding cycles, expression in females of male-specific biomarkers, development of male secondary sexual characteristics in females, and changes in the expression of steroidogenic genes. A recent in vitro study showed that a number of representatives from this class of progestins were potent agonists of fathead minnow androgen receptor (AR) and only weak agonists of progesterone receptor (PR) from the same species. This confirms that synthetic progestogens derived from 19-nortestosterone function as AR agonists in otomorphs, which express a single AR subtype.

Differential ligand selectivity of androgen receptors α and β from Murray-Darling rainbowfish (Melanotaenia fluviatilis).

Androgen receptors (ARs) mediate the physiological effects of androgens in vertebrates. In fishes, AR-mediated pathways can be modulated by aquatic contaminants, resulting in the masculinisation of female fish or diminished secondary sex characteristics in males. The Murray-Darling rainbowfish (Melanotaenia fluviatilis) is a small-bodied freshwater teleost used in Australia as a test species for environmental toxicology research.

Assessment of multiple hormonal activities in wastewater at different stages of treatment.

Changes in the endocrine potency of municipal wastewater at 3 wastewater treatment plants (WWTPs) in Australia were investigated using a panel of in vitro receptor-driven transactivation assays. The assays were based on human estrogen receptor α, androgen receptor, progesterone receptor, glucocorticoid receptor, and peroxisome proliferator-activated receptor γ2. Total removal efficiencies for estrogenic activity in the dissolved phase were 79.

Cytotoxicity of binary mixtures of human pharmaceuticals in a fish cell line: approaches for non-monotonic concentration-response relationships.

Predicting the effects of mixtures of environmental micropollutants is a priority research area. In this study, the cytotoxicity of ten pharmaceuticals to the rainbow trout cell line RTG-2 was determined using the neutral red uptake assay. Fluoxetine (FL), propranolol (PPN), and diclofenac (DCF) were selected for further study as binary mixtures.

Benchmarking organic micropollutants in wastewater, recycled water and drinking water with in vitro bioassays.

Thousands of organic micropollutants and their transformation products occur in water. Although often present at low concentrations, individual compounds contribute to mixture effects. Cell-based bioassays that target health-relevant biological endpoints may therefore complement chemical analysis for water quality assessment.

Dietary fish oil replacement with canola oil up-regulates glutathione peroxidase 1 gene expression in yellowtail kingfish (Seriola lalandi).

The marine carnivore yellowtail kingfish (YTK, Seriola lalandi) was fed diets containing 5% residual fish oil (from the dietary fish meal) plus either 20% fish oil (FO), 20% canola oil (CO), 20% poultry oil (PO), 10% fish oil plus 10% canola oil (FO/CO) or 10% fish oil plus 10% poultry oil (FO/PO) and the effects on fish growth and hepatic expression of two glutathione peroxidase (GPx 1 and GPx 4) and two peroxiredoxin (Prx 1 and Prx 4) antioxidant genes were investigated. Partial (50%) replacement of the added dietary fish oil with poultry oil significantly improved fish growth whereas 100% replacement with canola oil significantly depressed fish growth. The fatty acid profiles of the fish fillets generally reflected those of the dietary oils except that there was apparent selective utilization of palmitic acid (16:0) and oleic acid (18:1n-9) and apparent selective retention of eicospentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3).

A glutathione peroxidase 4 (GPx4) homologue from southern bluefin tuna is a secreted protein: first report of a secreted GPx4 isoform in vertebrates.

The antioxidant enzyme glutathione peroxidase 4 (GPx4) is capable of reducing complex lipid hydroperoxides in addition to hydrogen peroxide and organic hydroperoxides. Mammals express three GPx4 isoforms that are targeted to nucleoli, mitochondria or cytosol via variable amino termini. To better understand the role of this important antioxidant enzyme in marine finfish, we determined the subcellular localisation of a GPx4 homologue from southern bluefin tuna (Thunnus maccoyii; SBT).

Use of fluorogenic probes to differentiate between hydrophilic and lipophilic antioxidant activity in a fish cell line.

In finfish aquaculture, dietary antioxidants have been shown to improve indicators of general fish health and to inhibit the oxidative deterioration of polyunsaturated fatty acids. To facilitate the characterization of novel antioxidants or antioxidant mixtures, we developed assays for antioxidant activity in a fish cell line. We used 2',7'-dichlorodihydrofluorescein diacetate (H(2)DCFDA) to determine the protective effects of a panel of representative antioxidant compounds against the formation of reactive oxygen species (ROS) under conditions that promote oxidative stress, whereas protective effects against lipid peroxidation were measured using the thiobarbituric acid reactive substances (TBARS) assay and a novel implementation of 4,4-difluoro-5-(4-phenyl-1,3-butadienyl)-4-bora-3a,4a-diaza-s-indacene-3-undecanoic acid (C(11)-BODIPY(581/591)).

Development of a fish cell culture model to investigate the impact of fish oil replacement on lipid peroxidation.

Fish oils are rich in omega-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA), predominantly 20:5n-3 and 22:6n-3, whereas vegetable oils contain abundant C(18)-PUFA, predominantly 18:3n-3 or 18:2n-6. We hypothesized that replacement of fish oils with vegetable oils would increase the oxidative stability of fish lipids. Here we have used the long established and easily cultivated FHM cell line derived from the freshwater fish species fathead minnow (Pimephales promelas) to test this hypothesis.

Naturally occurring DNA transfer system associated with membrane vesicles in cellulolytic Ruminococcus spp. of ruminal origin.

A genetic transformation system with similarities to those reported for gram-negative bacteria was found to be associated with membrane vesicles of the ruminal cellulolytic genus Ruminococcus. Double-stranded DNA was recovered from the subcellular particulate fraction of all the cellulolytic ruminococci examined. Electron microscopy revealed that the only particles present resembled membrane vesicles.